SU92014A1 - Hammer mill for fine grinding of slag and other building materials - Google Patents

Description

Known hammer mills for fine grinding of slag and other building materials with a rotor mounted in a housing equipped with a grate, the distance between the grate bars is 6-8 mm, intended for grinding granulated slag and boiler slags in cement production, as well as fine grinding of active or inert additives: slag, lime, gypsum, ash, etc., are inefficient due to the filling of the inter-grate spaces of the lattice with the material being processed.

The peculiarity of the described mill is that in it, in order to eliminate the blockage of the grate, a rotor is installed, which rotates with a peripheral speed of over 90 m / s.

The grinding process in this hammer mill occurs due to hammering of the material to be milled and its particles at high speeds, at which they are abraded against each other and against the surface of the grinding chamber.

FIG. 1 shows a hammer mill, a longitudinal section; in fig. 2 is the same cross section; in fig. 3-bar sieve, cross section; in fig. 4 - the same, longitudinal section; in fig. 5- feeder, side view.

The mill consists of a frame / welded from channels, on which is welded the welded casing 2 of the mill and the engine that drives the hammer mill. On the receiving mouth of the 3 mills, a feeder is fixed, which provides uninterrupted and uniform power along the entire length of the receiving gap of the crushing chamber. Crushing chamber 4 is formed by a grid screen of grate. A cast-iron corrugated deck 5 is installed at the top of the chamber. The same deck 6 is installed on the left side of the chamber. Between the decks 7 on the side of the receiving opening a receiving slot of the chamber is formed. Inside the chamber, mounted on the main shaft 8, a disk rotor 9 rotates with hammers hinged between steel disks. The main shaft of the hammer mill is rotated in two roller bearings 10. The bodies of the liners are mounted on brackets welded to the frame of the machine.

No. 92014- 2 Machine rotor j: ocTOHT made of round steel wheels of the same size AND, spaced equally from each other, reinforced by two solid keys on the main shaft of the machine. The steel discs that make up the rotor of the machine have holes around the circumference, into which round rods are inserted, which are simultaneously tension bolts 12. Hammers 13 are freely suspended on the rods between the discs, the bolts are tightened with special nuts. Hammers are cast from manganese steel. To stiffen the rotor in the longitudinal direction, intermediate steel bushings 14 are placed on the main shaft between the disks; On the outside of each end disk, steel locking sleeves 15 on the thread are tightened with screws. The main shaft of the machine, on which the rotor of the hammer mill is fixed, receives rotation from the engine.

Stacked grate 16, cast from Hadfield steel, is a sieve 17. The sieve is mounted from two halves on rollers 18, which provides for its convenient extension and cleaning. The grate bars of each half of the sieve are inserted into two channels 19 to replace the protrusions on the working side of the grinding chamber with a measure of their wear; thus, each grate is used on both sides. The grate bars are located parallel to the axis of the hammer mill and provide solid holes at a distance of 6-8 mm, which is necessary for the ground slag particles to pass through the sieve. Due to the high speed of the rotor, solid holes do not affect the deterioration of the quality of the material being ground. The use of protrusions in a diaphragm sieve increases the surface of the crushing chamber, since it also causes additional material destruction during impact and friction against the protrusions of the sieve. Hammers / plate-shaped rectangular shapes that simplify manufacture and allow sharpening them. Holes are drilled around the circumference of the rotor discs to reposition the hammers as they wear out the outer corners.

The feeder is a wing drum 21 rotating inside the housing 20, forming bucket sections. Rotating the drum provides a continuous flow of material from the hopper to the hammer mill; on the shaft of the feeder sits, besides the drum, a ratchet wheel. From the rotation of the eccentric by the connecting rod 22 mounted on the link, the link fluctuates. Along the backstage, a slider 23 can be moved, to which two lugs 24 and 25 are attached, equipped with feed latches at the end. Using the set screw and nut can move the slide along the graduated scale. If the slider moves up, the amplitude of the oscillation of the link decreases; oscillating t-rails report periodic rotation to the ratchet. If the link is moved with the angular lever to the left, the lower pawl 26 rotates the wheel. During the reverse movement, the upper pawl 27 operates and the ratchet wheel rotates in the same direction. The amount of material supplied by the feeder depends on the average angular velocity of the feeder shaft, which can be adjusted by the indicated screw handle.

The material entering the crushing chamber through the feeder drum is subjected to the impacts of rotating hammers directed by the centrifugal force along the rotor radius. Repeatedly hit by the hammer blows in the deck and rubbing the sieve protrusions and abrading the particles against each other, the material is finally crushed. Particles of crushed material passing through the sieve enter the expansion chamber located in the hammer mill. In the expansion chamber, due to a decrease in the speed of the ground material, the heaviest particles settle, and the mixture of air with the smallest

the particles are sucked off by a fan and carried to the filter cyclone. Heavy material particles settled in the chamber through a rotary lock are fed to the noria and fed back to the bunker of the hammer mill for re-crushing. Taking into account that the air flow rates in the expansion chamber and in the battery cyclone are maintained by the fan in accordance with the feed rate of the required size fractions of finely ground slag, particles whose feed rate is lower than the air velocity are transported through the diffuser into the filter cyclone. Particles with a feed rate higher than the speed of the air flow fall out of it and settle in the expansion chamber. In the filter cyclone otfeivanie occurs under the action of gravitational forces. The bulk of the finely ground material is deposited in the cyclone bunker, and air containing no more than 1-2% of the smallest cement particles is pumped through the fan wheel. The presence of an expansion chamber ensures the normal operation of the machine without braking the rotor of the mill mill in the mass of unmilled material, which reduces the engine overload. Stones and pieces of metal that have accidentally entered the crushing chamber, which must be retained on the electromagnetic separator, are ejected by inertia into the trap that is present in the housing over the entire width of the grinding chamber.

Subject invention

Hammer mill for fine grinding of slag and other building materials with a rotor installed in a housing equipped with a grate, the distance between the grate bars is 6-8 mm, and with this, in order to eliminate clogging of the grate, a rotor is installed Swinging at a speed of over 90 m / s.

 3 920I

22

20 27

FIG 5